Thursday, September 9, 2010

There was, apparently, no briefing today on the Deepwater Oil Spill. However RockyPaloma has put up a number of videos on Youtube showing an internal video inspection of the blowout preventer (BOP) with pictures of severe metal erosion.

And one showing the deformed drill pipe surrounded by the eroded annular preventer, gives some indication of the extent to which sand in the oil/natural gas/water mix was eating out the internal surfaces of the BOP, and allowing the leak to increase in size, over time, a point that I made, quite early in the proceedings.

MoonofA has given a more concise, yet comprehensive picture of what the camera saw, together with a sketch of the ram assembly showing what the various parts are that are shown in the video. Ricx also adds an interesting question.

For those who need reminding of the structure of the BOP, PhilMB has put up a graphic section of the structure, so that you can tell which view corresponds with what.

The problem, of course, is that it is not clear when the different stages of erosion occurred. While there is some, there is not a lot of difference in wear surface patterns under differing flow regimes, containing different abrasive concentrations at different flow speeds. Because the erosion took place over the relatively long time intervals that it did, I am surprised in a way that it did not do a lot more damage than it did. Certainly some of the gaps might have been filled if the top hat “junk shots” had been continued longer than they were.

The investigation is, however, still in its early stages, and I imagine that there will be a lot more expert testimony on the structures (which likely means that at some time they will be cut apart to provide sectioned specimens). That is not going to be a simple short-term operation or investigation. And at the same time the pressure is now no longer on the relief well to seal in the oil and gas, so that too is likely to proceed at a gentler pace.

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Waterjetting Index

After writing about Waterjet Technology for a couple of years at this site I have created an index, hopefully this will be updated monthly and can be found at: Waterjet Index .

The Archive of Oil and Gas and Coal Posts

About ten years ago I began to write a blog, and after a time that transformed into co-founding The Oil Drum. Move on a few years, and at the end of 2008 I turned from being an editor there to this blog, although the OGPSS series continued to be posted, on Sundays, at TOD as their weekly Tech Talk. Some of the industrial technical descriptions of oilwell formation and coal mining are relatively timeless and useful, and so are listed below.

Along the way I became similarly cynical about some of the facts being bruited about Climate Change, and did a little study, which is documented here as the State Temperature Analysis Series. It showed that the UHI is real and that there is a log:normal relationship between population and temperature (which is also related to altitude and latitude). You can read the individual state studies, which are listed below. There will still be the occasional post on this topic.

Just this last year I was asked to write a weekly blog on the application of High-Pressure waterjetting – which is the subject that I specialized in for four decades.That too is now, therefore, a part of the contribution.

And, in my retirement, I have become curious about Native Americans and what they looked like.And so I am now learning Poser and related programs, and may inject both posts and the odd illustration – helped by the many real artists who work in that medium, as I read and try and comprehend what went on in the depths of The Little Ice Age (around 1600 – 1700).

Because I am a Celt, there will also be the odd post on my lineage and some of the DNA studies that relate to history.

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Units and Conversions

One of the problems in following stories in different countries is that they use different units and symbols. This can be a bit confusing, and so, where I can, I will try and standardize on the unit of barrel/day, or bd for oil. I will also use a thousand cubic ft kcf for natural gas. Prices will also be standardized, when I can, in $/kcf for natural gas, $/barrel for oil, and $/gallon for gasoline.

In larger units volumes a thousand barrels a day becomes 1 kbd and a million barrels a day becomes 1 mbd. For natural gas a million cu ft per day will be 1 mcf. (In many quotes this has appeared as 1 MMcf).

A billion cu. ft. is 1,000 mcf. Note that a cubic foot of gas produces 1,030 Btus - so to simplify 1 million Btu's is approximately 1 kcf, or 28.3 cu.m. of natural gas equivalent.

A ton of oil is 7.33 barrels. (Mainly used in Eastern Europe).

Since not all posts before this show these units - note that this change happened on March 3, 2009.